I am not quite certain what the advantages/disadvantages are of using LDV vs DCDC if you are using an external regulator. In my case i use a LiPo battery outputting ~4.2V so i need to drop the voltage down to something 1.8-3.6V for the nRF51822.
Would it be more power efficient to use the LDO @ 1.8V or DCDC at some higher voltage like 2.0V? Either is an option im just not sure since i hear DCDC is more power efficient than LDO.